Question

我有两个数据表dtAllTicket(ticket_id, name)和dtSpecialTicket(ticket_id)

首先，我要检索dtAllTicket中的所有行，其中ticket_id中不存在dtSpecialTicket

然后，我想从dtSpecialTicket检索所有行，其中两个表中都存在ticket_id

Answer 1

您可以使用Linq-To-DataSet和Enumerable.Join，例如：

var specialInBoth = from rowSpecial in dtSpecialTicket.AsEnumerable()
                    join rowAll in dtAllTicket.AsEnumerable()
                    on rowSpecial.Field<int>("ticket_id") equals rowAll.Field<int>("ticket_id") 
                    select rowSpecial;

var specialIDs = new HashSet<int>(dtSpecialTicket.AsEnumerable()
    .Select(row => row.Field<int>("ticket_id")));
var allNotInSpecial = from rowAll in dtAllTicket.AsEnumerable()
                      let id = rowAll.Field<int>("ticket_id") 
                      where !specialIDs.Contains(id)
                      select rowAll;

Answer 2

var dtUpdate = new HashSet<int>(_dtTicket.AsEnumerable()
                        .Select(row => row.Field<int>("ticket_id")));

var varUnmatched = from all in _sourceDataTable.AsEnumerable()
                   let id = all.Field<int>("ticket_id")
                   where !dtUpdate.Contains(id)
                   select all;
DataTable dtInsert = varUnmatched.CopyToDataTable();

var varMatched = from all in _sourceDataTable.AsEnumerable()
                 let id = all.Field<int>("ticket_id")
                 where dtUpdate.Contains(id)
                 select all;
DataTable dtDelete = varMatched.CopyToDataTable();

从两个数据表中选择匹配和不匹配的行

2 个答案: